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Use AbortSignal instead of cancelWatch
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@kenchris
kenchris committed Nov 27, 2018
1 parent 336e6af commit e00c38e
Showing 1 changed file with 71 additions and 81 deletions.
152 changes: 71 additions & 81 deletions index.html
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Expand Up @@ -1440,7 +1440,6 @@ <h2>The <dfn>NFCRecordType</dfn> enum</h2>
Promise&lt;void&gt; push(NFCPushMessage message, optional NFCPushOptions options);
Promise&lt;void&gt; cancelPush(optional NFCPushTarget target="any");
Promise&lt;long&gt; watch(MessageCallback callback, optional NFCWatchOptions options);
Promise&lt;void&gt; cancelWatch(optional long id);
};

callback MessageCallback = void (NFCMessage message);
Expand All @@ -1453,12 +1452,6 @@ <h2>The <dfn>NFCRecordType</dfn> enum</h2>
The <dfn>MessageCallback</dfn> is a callback function that must be
provided to <code><a href="#dom-nfc-watch">watch()</a></code> metod.
</p>
<p class="note">
In later versions <code>cancelPush()</code> and <code>cancelWatch()</code>
may be obsoleted by <a href="https://github.com/domenic/cancelable-promise">
cancelable Promises</a> used with <code>push()</code> and
<code>watch()</code>, respectively.
</p>
<section><h3>Internal slots of NFC</h3>
<p>
The <a>NFC</a> object is created with the <a>internal slots</a>
Expand Down Expand Up @@ -1661,6 +1654,7 @@ <h2>The <dfn>NFCPushTarget</dfn> enum</h2>
NFCRecordType recordType;
USVString mediaType = "";
NFCWatchMode mode = "web-nfc-only";
AbortSignal? signal;
};
</pre>
<p>
Expand Down Expand Up @@ -1690,6 +1684,10 @@ <h2>The <dfn>NFCPushTarget</dfn> enum</h2>
<code><a>NFCWatchMode</a></code> value telling whether only
<a>Web NFC content</a> or any <a>NFC content</a> will be watched.
</p>
<p>
The <dfn>NFCWatchOptions.AbortSignal</dfn> property allows to abort / cancel
the watch.
</p>

<pre
title="Filter accepting only JSON content from https://www.w3.org"
Expand Down Expand Up @@ -2613,10 +2611,10 @@ <h2>The <dfn>NFCWatchMode</dfn> enum</h2>
<a>URL pattern</a>s used in <a>NFC watch</a>es.
</p>
<p>
An <dfn>NFC watch</dfn> is referring to a
<code><a>NFCWatchOptions</a></code> filter saved together with the
<code><a>NFC</a></code> instance it belongs
to, and a locally unique identifier which is used for cancellation.
An <dfn>NFC watch</dfn> is referring to a tuple of a <code><a>Promise</a></code>,
a <code><a>NFCWatchOptions</a></code> and a <code><a>MessageCallback</a></code>.
</p>
<p>
The section <a href="#steps-receiving">
Receiving and parsing content</a> uses <a>NFC watch</a>es to match
incoming <a>NFC content</a>.
Expand All @@ -2626,62 +2624,85 @@ <h2>The <dfn>NFCWatchMode</dfn> enum</h2>
same <a>origin</a> create filters which are in OR relationship.
</p>
<p>
When the <code>
<dfn>NFC.watch</dfn>(<var>callback</var>, <var>options</var>)
</code> method is invoked, the UA MUST run the following
When the <code><dfn>NFC.watch</dfn></code> method is invoked, the UA
MUST run the following
<dfn id="steps-watch">NFC watch algorithm</dfn>:
<ol>
<li>
Let <var>promise</var> be a new <a><code>Promise</code></a> object.
</li>
<li>
Return <var>promise</var> and continue the following steps
<a>in parallel</a>.
Let <var>p</var> be a new <a><code>Promise</code></a> object.
</li>
<li>
If any exception occurs while running these steps, reject
<var>promise</var> with that exception and abort these steps.
Let <var>callback</var> be the first argument.
</li>
<li>
If there is no support for the functionality of receiving data from
an <a>NFC peer</a> or <a>NFC tag</a> in proximity range, reject
<var>promise</var> with <code>"NotSupportedError"</code> and
abort these steps.
Let <var>options</var> be the second callback.
</li>
<li>
If the <a>obtain watch permission</a> steps return
<code>false</code>, then reject <var>promise</var> with
<code>"SecurityError"</code> and abort these steps.
Let <var>signal</var> be the options’ dictionary member of the same
name if present, or null otherwise.
</li>
<li>
If this is the first watch being set up, then make a request to
all <a>NFC adapter</a>s to listen to <a>NDEF message</a>s.
If <var>signal</var>’s aborted flag is set, then reject <var>p</var>
with an <code>"AbortError"</code> DOMException and return <var>p</var>.
</li>
<li>
If the request fails, reject <var>promise</var> with
<code>"NotSupportedError"</code> and abort these steps.
</li>
<li>
If the <var>options</var>.url is not an empty <code>String</code>
and it is not a <a>valid URL pattern</a>, throw <code>"SyntaxError"</code>
exception and abort these steps.
</li>
<li>
Let <var>watchId</var> be a number that will identify this
<a>NFC watch</a>.
If there is no support for the functionality of receiving data from
an <a>NFC peer</a> or <a>NFC tag</a> in proximity range, reject
<var>p</var> with <code>"NotSupportedError"</code> and return <var>p</var>.
</li>
<li>
Add <var>watchId</var>, <var>options</var>, and <var>callback</var>
Add <var>p</var>, <var>options</var>, and <var>callback</var>
together as an <a>NFC watch</a> to <var>this@[[\watchList]]</var>.
</li>
<li>
Resolve <var>promise</var> with <var>watchId</var>.
</li>
<li>
If the <a>browsing context</a> loses focus (e.g. the user navigated
to another page), then the registered watches still SHOULD continue
to exist, but SHOULD become paused, i.e. the UA SHOULD NOT check
and use them until the focus is regained.
If <var>signal</var> is not null, then
<a href="https://dom.spec.whatwg.org/#abortsignal-add">
add the following abort steps</a> to <var>signal</var>:
<ol>
<li>
Remove the <a>NFC watch</a> from <var>this@[[\watchList]]</var>
</li>
<li>
If <var>this@[[\watchList]]</var> is empty, then make a request
to stop listening to <a>NDEF message</a>s on all <a>NFC adapter</a>s.
</li>
<li>
Reject <var>p</var> with an <code>"AbortError"</code> DOMException
and abort these steps.
</li>
</ol>
</li>
<li>
Run the following steps <a>in parallel</a>:
<ol>
<li>
If the <a>obtain watch permission</a> steps return
<code>false</code>, then reject <var>p</var> with
<code>"SecurityError"</code> and return <var>p</var>.
</li>
<li>
If this is the first watch being set up, then make a request to
all <a>NFC adapter</a>s to listen to <a>NDEF message</a>s.
</li>
<li>
If the request fails, reject <var>p</var> with
<code>"NotSupportedError"</code> and return <var>p</var>.
</li>
<li>
If the <var>options</var>.url is not an empty <code>String</code>
and it is not a <a>valid URL pattern</a>, throw <code>"SyntaxError"</code>
exception and return <var>p</var>.
</li>
<li>
Resolve <var>p</var>.
</li>
<li>
If the <a>browsing context</a> loses focus (e.g. the user navigated
to another page), then the registered watches still SHOULD continue
to exist, but SHOULD become paused, i.e. the UA SHOULD NOT check
and use them until the focus is regained.
</li>
</ol>
</li>
</ol>
</p>
Expand Down Expand Up @@ -2724,38 +2745,7 @@ <h2>The <dfn>NFCWatchMode</dfn> enum</h2>
</ol>
</p>
</section> <!-- watch() method -->

<!-- The cancelWatch() method -->
<section><h3>The <strong>cancelWatch</strong>() method</h3>
<p>
When the <code><dfn>NFC.cancelWatch</dfn>(id)</code> method is
invoked, the UA MUST return a <a><code>Promise</code></a>
<var>promise</var> and run the following steps <a>in parallel</a>.
<ol id="steps-cancelWatch">
<li>
If the parameter <var>id</var> is <code>undefined</code>, then
remove all watches and filters set by successive calls of the
<code><a>NFC watch</a>()</code> method on all <a>NFC adapter</a>s.
</li>
<li>
Otherwise, if the parameter <var>id</var> matches the local
identifier of one of the previously set up watches, remove the
corresponding watch.
</li>
<li>
Otherwise, reject <var>promise</var> with
<code>"<a>NotFoundError</a>"</code> and abort these steps.
</li>
<li>
If there are no more watches, then make a request to stop listening
to <a>NDEF message</a>s on all <a>NFC adapter</a>s.
</li>
<li>
Resolve <var>promise</var>.
</li>
</ol>
</p>
</section> <!-- cancelWatch() -->

</section>

<section id="steps-receiving">
Expand Down

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